JERUSALEM (Reuters) - Palestinian civilian deaths in the Gaza Strip were a "product of circumstance," Israeli Foreign Minister Tzipi Livni said on Monday.

"We had to carry out this operation. I am at peace with the fact that we did it," Livni, a centrist who is running for prime minister in a February 10 election, told Israel Radio.

Israel's Gaza offensive, launched on December 27 to counter Palestinian rocket attacks and suspended on Sunday, killed more than 1,300 Palestinians. Gazan rights groups said 700 civilians died, many of them children.

Asked about the civilian death toll, Livni said, "it was a product of circumstance." She blamed the ruling Islamist Hamas in Gaza for fighting from within population centers.

"We seek out the terrorists, and it can happen that civilians are sometimes hurt in the fight against terror."

She added: "We should not take this lightly. These matters will present us with a complicated task ... The consequences, in the context of civilians casualties, are something we have to deal with, among ourselves and in facing the world."

In Israel, which lost 10 soldiers in combat and three civilians to rockets, the offensive was popular given anger at Islamist Hamas and frequent cross-border salvoes from the Gaza Strip, which Israeli forces and settlers quit in 2005.

But Israelis are also mindful of criticism from Western powers which worry that the suffering in impoverished Gaza could sap support for Hamas's secular rival, Palestinian President Mahmoud Abbas, and his peace talks with the Jewish state.

Rights group Amnesty International added its voice to those calls on Monday, saying Israel's use of white phosphorus munitions -- which can cause extreme burns -- in densely populated areas of Gaza was indiscriminate and therefore constituted a war crime.

Israel has said it used all weapons in Gaza within the limits of international law.

Palestinians have long demanded international prosecution of Israel's military crackdowns. Yet legal frameworks are lacking.

The International Criminal Court in The Hague has no jurisdiction to investigate in the Gaza Strip, as it is not a state. Though the Palestinian Authority has been functioning as an interim sovereign polity since 1993, it was forced out of Gaza last year by Hamas after the Islamists won an election.

And while Israel has not signed the Rome Statute that enshrined the ICC, it can still be investigated, but that would require a U.N. Security Council mandate. Any such proposal would likely be vetoed by Israel's ally, the United States.

Some European nations allow for war-crimes lawsuits to be filed privately against members of Israel's security services.

Though such efforts have not yet yielded a trial, Israel's Yedioth Ahronoth newspaper said the military was warning its top brass to think twice about traveling to Europe.

During the Gaza fighting, Israel's armed forces often warned Palestinians to leave their homes ahead of attacks. But many complained that there was no reliable escape, especially as U.N. schools serving as havens were repeatedly shelled.

Another charge, made by U.N. officials and legal experts, is that Israel may have violated a principle of "proportionality" in tackling outgunned Palestinian guerrillas.

Israel says it resorted to the force required to minimize its losses during urban warfare against Hamas.

"There was no excessive use of firepower," a top Israeli infantry officer, Colonel Ilan Malka, told reporters in a rare briefing on Monday. Israel has otherwise largely curbed media access to the battle zones and military personnel.

"I will not send 10 soldiers into a house suspected of being booby-trapped, and where they could get blown up, before I have created the conditions for their entry," Malka said. "Had Hamas wanted to protect them (residents) it would not have booby-trapped the house."